Plank with Punch
To do the Plank with Punch, start in a forearm front plank position with your feet about hip-width to shoulder-width apart and your elbows under your shoulders. Bracing your abs and engaging your quads and glutes, punch one hand out to the side at about shoulder height. Move in a controlled fashion and try not to really rotate or let your butt go up in the air as you punch out.
Stabilize and fight rotation as you punch to the side then come back into the plank position and punch out to the other side. Keep alternating punches at a controlled pace.
Try to keep your core braced and your hips as stabilize as possible as you alternate punches. Do not “bounce” as you alternate sides. Make your core really work to fight the urge to rotate.